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Effect of structure on the thermal degradation and flame retardancy of hexolic anhydride based polyesters
Author(s) -
Vijayakumar Chinnaswamy Thangavel,
Sivasamy Palanichamy,
Lederer Klaus
Publication year - 2002
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/1521-3900(200205)181:1<253::aid-masy253>3.0.co;2-v
Subject(s) - polyester , thermogravimetric analysis , diol , materials science , thermal stability , butanediol , polymer chemistry , condensation polymer , organic chemistry , chemistry , catalysis , composite material , fermentation
Based on the anhydrides like hexolic (5,6,7,8,10,10‐hexachloro ‐3a,4,4a,5,8,8a,9,9a‐octahydro‐5,8‐methanonaphtho‐[2,3‐c]‐furan‐1,3‐dione), maleic and phthalic and diols like 1,4‐butanediol, cis ‐2‐butene‐1,4‐diol and 2,3‐dichloro‐2‐butene‐1,4‐diol, a family of polyesters has been synthesized using azeotropic condensation technique. The structural characterizations of the polyesters have been carried out using infra‐red, 1 H ‐ and 13 C‐ nuclear magnetic resonance spectroscopic methods. The thermal properties of the polyesters have been studied using thermogravimetric technique. The off‐line pyrolysis of these materials was done. The qualitative and semi‐quantitative analyses of the volatiles as well as the heavy mass fractions of the degradation products were carried out using a gas chromatograph coupled to a mass selective detector (GC‐MSD). Thermogravimetric data indicate that the thermal stability and the char residue of the polyester resins decrease in the order 1,4‐butanediol based> cis ‐2‐butene‐1,4‐diol based>2,3‐dichloro‐2‐butene‐1,4‐diol based polyesters. The GC‐MSD data indicate that the amount of flame cooling agents (hexa‐, isomeric penta‐, tetra‐ and isomeric tri‐chlorocyclopentadienes) produced during the pyrolysis of the polyesters increases in the order 2,3‐dichloro‐2‐butene‐1,4‐diol based< cis ‐2‐butene‐1,4‐diol based<1,4‐butanediol based polyesters. The trends observed in these two parameters which are contributing factors to the flame retardancy of the polyester materials were suitably explained on the basis of the effect of the structural changes in the diol part of the polyesters on the primary degradation mechanism, the β‐chain scission process.